The present invention relates to an arrangement in a sewing machine, comprising a needle bar having a needle, a feed dog for feeding a fabric to be sewn, and a vertically movable presser bar having a presser foot and a presser spring. The presser bar is actuated by a power-driven actuating means connected to the presser spring and slidable in parallel with the presser bar. The actuating means is movable relative to the presser bar to control the presser foot pressure and to engage the presser bar in order to raise and lower the presser foot during the sewing procedure in accordance with a predetermined program.
A conventional, stationary presser foot creates a braking action on an upper fabric layer due to friction between the fabric and the presser foot. The friction results in a risk of mutual displacement of the fabric layers in that the distance of feeding of the upper layer will be shorter than that of the lower layer which is in direct contact with the feed dog. As is easily seen, such mutual displacement of the fabric layers will have a negative effect on the sewing performance. The problem is particularly evident in the case of material providing great friction when engaging the presser foot, but also when sewing soft, compressible fabric material.
In order to provide a solution to the above problem it is known to use an arrangement having a slidably journalled presser foot. Raising movement of the presser foot is provided by the drive mechanism of the needle bar. However, in such an arrangement it is not possible to obtain raising and lowering of the presser foot at the appropriate moments during the sewing procedure, and the performance of the arrangement has therefore not appeared to be satisfactory.